25 years and counting for Hubble

NASA's telescope survived early trouble to provide years of iconic images

By Dennis Overbye, New York Times

Published 11:06 pm, Friday, April 24, 2015

Photo: NASA

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In this April 25, 1990 photograph provided by NASA, most of the giant Hubble Space Telescope can be seen as it is suspended in space by Discovery's Remote Manipulator System (RMS) following the deployment of part of its solar panels and antennae. This was among the first photos NASA released on April 30 from the five-day STS-31 mission. The Hubble Space Telescope, one of NASA'S crowning glories, marks its 25th anniversary on Friday, April 24, 2015. With more than 1 million observations, including those of the farthest and oldest galaxies ever beholden by humanity, no man-made satellite has touched as many minds or hearts as Hubble. (NASA via AP) ORG XMIT: NY122 less

In this April 25, 1990 photograph provided by NASA, most of the giant Hubble Space Telescope can be seen as it is suspended in space by Discovery's Remote Manipulator System (RMS) following the deployment of ... more

Few icons of science have had such a perilous existence, surviving political storms, physical calamities and the simple passage of time in the service of cosmic exploration.

In 1946, the astronomer Lyman Spitzer Jr. had a dream. A telescope in space, above the unruly atmosphere, would be able to see stars unaffected by the turbulence that blurs them and makes them twinkle. It would be able to see ultraviolet and infrared emissions that are blocked by the atmosphere and thus invisible to astronomers on the ground.

It took more than three decades for the rest of the astronomical community, NASA and Congress to buy into this dream, partly as a way to showcase the capabilities of the space shuttle, still in development then, and the ability of astronauts to work routinely in space. By the time the telescope was launched into space from the space shuttle Discovery on April 25, 1990, it had been almost canceled at least twice and then delayed after the explosion of the shuttle Challenger in 1986.

When the Hubble was finally deployed, NASA's spinmasters were instantly at the top of their game, hailing it as the greatest advance in astronomy since Galileo.

And it might have been except for one problem: The telescope couldn't be focused. Instead, within days it became a laughingstock

Designed using spy satellite technology, Hubble had an 8-foot mirror, just small enough to fit into the space shuttle cargo bay. But because of a measuring error during a testing process that was hurried to save money, that big mirror wound up misshapen, polished four-millionths of an inch too flat, leaving the telescope with blurry vision. It was the kind of mistake, known as a spherical aberration, that an amateur astronomer might make, and it was a handful of astronomers who first recognized the flaw — to the disbelief and then the dismay of NASA engineers and contractors.

For bright objects, astronomers could correct for the flaw with image processing software. But for the fainter parts of the universe, the Hubble needed glasses.

NASA scientists shrugged off their heartbreak and worked to figure out a way to provide corrective lenses. Three years later, the space shuttle Endeavour and a repair crew led by Story Musgrave rode to the rescue. In five tense days of spacewalks, they replaced the telescope's main camera and installed tiny mirrors designed to correct the Hubble's vision.

The rest of the universe snapped into crystalline focus. And NASA could stop holding its breath.

The Hubble was the first big-deal telescope of the Internet age, and its cosmic postcards captivated the world. Trained on a patch of sky known as the Hubble Ultra Deep Field in 2010, the telescope's keen eye discerned swarms of baby galaxies crawling out of the primordial darkness as early as only 600 million years after the Big Bang.

And it took one of the first visible-light photos of a distant planet, Fomalhaut b, orbiting its star. In perhaps its most iconic image, "Pillars of Creation," the Hubble recorded baby stars burning their way out of mountains of gas and dust in a stellar nursery known as the Eagle nebula.

The Hubble today is more powerful than its designers dreamed, and has a good chance of seeing the arrival of its successor, the James Webb Space Telescope, due in 2018.